Double-hung windows include two window sashes typically mounted for vertical movement along adjacent parallel tracks in a window frame. Traditional double-hung window designs provide poor washability, because it is difficult for a person located inside a structure in which the window is installed to wash the outside of the window pane. To fully wash the outer surface of such windows (which outer surface is the one which is most often in need of cleaning), the person cleaning the window must typically go outside the dwelling. This is not only extremely inconvenient, as the person has to walk significant distances merely to wash both sides of a single window, but it can also force a window washer, when trying to wash double and single-hung windows located at significant heights, to face the undesirable choice of either risking injury by climbing to that height or doing a relatively poor job of washing by merely reaching from a distance with a hose or a special long pole apparatus of some type. Such cleaning is still further complicated where there are screens or storm windows that must be removed prior to washing.
To overcome this problem, windows of this type have developed that enable one of the sashes to be tilted inwardly to gain access to the outside surface of the window pane from within the structure. Various types of latching mechanisms have been developed to enable the sash to secure the sash in place in the frame, but to also enable tilting the sash by operating the latches. A common arrangement has such latches positioned in opposite ends of a top horizontal rail of the upper and/or lower sash, with each latch typically including a tongue or plunger which during normal operation extends out from the side of the sash into the sash track in the window frame to guide the sash for typical vertical movement. The tongue or plunger of each latch is retracted when washing is desired to free the top rail of the sash from the track so that the sash may be suitably pivoted inwardly about pivots guiding the bottom rail of the sash in the track and thereby allow the washer to easily reach the outside surface of the window pane of that sash.
The tongue or plunger in many of the prior art latches is usually biased outwardly into the track by a spring structure or the like, with the tongue retracted inwardly by the washer manually pulling the tongues in toward the center of the top rail against the force of the spring as, for example, in the mechanism disclosed in U.S. Pat. No. 5,139,291. A drawback of such mechanisms, however, is that both latches must be operated simultaneously, requiring that the operator use both hands. Moreover, simultaneous operation of latch controls spaced at the far edges of the sash can be awkward, especially for wide windows. Another mechanism, disclosed in U.S. Pat. No. 5,992,907, commonly owned by the owners of the present invention and hereby fully incorporated herein by reference, has a lever operably coupled with a check rail lock assembly that simultaneously operates remotely located tilt latch assemblies.
Other mechanisms linking tilt latches with a single control that also locks the sashes together are well known. For example, U.S. Pat. No. 5,398,447 (the '447 patent) discloses a tilt lock latch mechanism wherein a lever positioned proximate the center of the top rail of a lower sash may be rotated in one direction to engage a keeper positioned on the upper sash proximate the lever or in the opposite direction to operate remotely located tilt latches to enable tilting of the lower sash for cleaning. U.S. Pat. No. 5,791,700 (the '700 patent) discloses a tilt lock latch mechanism wherein a single control lever operates both sash locks and remote tilt latches. To accomplish this, the control lever is selectively rotatably positionable in three discrete positions: (1) a first position wherein the sash locks and the tilt latches are engaged; (2) a second position wherein the sash locks are disengaged to enable sliding of the sashes but the tilt latches are still engaged; and (3) a third position wherein the sash locks and the tilt latches are disengaged to enable sliding of the window. Similarly, U.S. Pat. No. 6,817,142 (the '142 patent) and its continuation U.S. application Ser. No. 10/959,696 also disclose a tilt lock latch mechanism having such a three position control lever.
Each of the above described mechanisms, however, has certain drawbacks. The '447 patent mechanism, while generally simple, requires rotation of the control lever in opposite directions from a center position for unlocking and tilting. This is inconvenient and may result in unintended tilting operation of the window if an inexperienced user seeking merely to unlock the window rotates the lever in the wrong direction. Also, the '447 patent mechanism requires that a separate control be manipulated by the operator to maintain the control lever in a desired position. The '700 patent mechanism, while enabling same-direction rotation of the control lever, is relatively complex, and may be expensive to manufacture and difficult to install and adjust. The '142 patent mechanism may be difficult to adjust, requiring partial disassembly and manipulation of a screw on the tilt latches for tensioning the strap connecting the control lever with the tilt latches. Moreover, the '142 patent describes a separate button that must be manipulated for engaging or releasing the tilt latches. This may be confusing for a user and result in frustration when attempting to tilt the window for cleaning, or in failure to properly reengage the tilt latches when cleaning is complete.
Another mechanism, described in U.S. Pat. No. 6,877,784, includes a rotary lever with sash lock that actuates remote tilt latches through an extensible member. A drawback of this mechanism, however, is that it is relatively complex, including a spring-loaded control lever and a pivoting trigger release mechanism in each of the tilt latches, making it relatively more expensive to produce and reducing reliability. Further, there are no simple means provided for attaching the extensible member to the tilt latches, nor is any means for adjusting length and tension of the extensible member provided.
U.S. patent application Ser. No. 10/289,803 discloses a similar tilt lock latch mechanism including a three-position control lever that actuates a sash lock as well as remotely located tilt latches. One drawback of this mechanism, however, is that a relatively complicated fastener arrangement is used for connecting the actuator spool to the tilt latch connector, affecting cost of manufacture and usability of the mechanism. Also, the tilt latches are not equipped with any mechanism for holding the latches in the retracted position. When the window is tilted into position after cleaning, the protruding latch bolts may mar the window frame if the operator forgets to manually retract them. Moreover, a separate button is described that must be manipulated for engaging or releasing the tilt latches, thus complicating operation.
What is still needed is a low-cost combination tilt-lock-latch mechanism for a double hung window that is easy to install and adjust, and simple to use.